[MBDyn-users] File Driver

Andrea Zanoni a.zanoni.mbdyn at gmail.com
Fri Mar 24 17:08:56 CET 2017


Hi Franco,

i think that the "aircraft instrument" element exposes the angle of 
attack as a private data, so you could think of using it to make the AOA 
available to your controller.
Another possibility would be to use a combination of drives, obtained 
with the special "array", "mult" and "drive" drives, (this could be a 
bit cumbersome, though).
Also, you could use a symbolic "GiNaC" drive.

For the latter, you should have compiled MBDyn with GiNaC support. If 
you use MBDyn in a linux environment, this reduces to having the GiNaC 
library installed (see http://www.ginac.de/), along with its header 
files when configuring the package. In Debian-based distributions that 
is accomplished by installing the libginac-dev package, for Fedora is 
ginac-devel and for Arch it should be just ginac.

You should also have pkg-config installed and set the environment variables

LD_LIBRARY_PATH=/usr/local/lib
LD_RUN_PATH=/usr/local/lib
PKG_CONFIG_PATH=/usr/local/lib/pkgconfig/

when calling the configure script.

Cheers
Andrea

Il 24/03/2017 15:56, Franco Lovato ha scritto:
>
> Hello
>
>
> As suggested, I am trying to control the sail orientation by applying 
> a couple to its basis, where now there is a hinge. I am facing a 
> problem: I started from the example you sent me, but I don't 
> understand how to pass the angle of attack to the controller. The aoa 
> is the value I need to keep fixed, while the wind direction changes 
> during the simulation. I even tried to compute it from the velocities, 
> but the actuating force (a couple, in my problem) can't take an 
> expression as controlled variable.
>
> There is also the possibility that I misunderstood how the controller 
> is set.
>
>
> Could you please suggest me a way to make it work?
>
>
> Thank you
>
> Franco Lovato
>
> ------------------------------------------------------------------------
> *Da:* Andrea Zanoni <a.zanoni.mbdyn at gmail.com>
> *Inviato:* mercoledì 22 marzo 2017 19.05.40
> *A:* Franco Lovato
> *Cc:* mbdyn-users at mbdyn.org
> *Oggetto:* Re: [MBDyn-users] File Driver
> I see... Interesting problem! I'm sorry I cannot be more of help for you.
> Would you mind to keep us updated on your progress here in the mailing 
> list, from time to time?
>
> Cheers
> Andrea

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